LEAF SPRING SUSPENSION
by Takeo De Meter
Today, all you hear and see is coil springs. They are soft, comfortable, give excellent axle travel, do not break often and are not very well suited for carrying heavy loads. Also, they tend to sag often.
For carrying heavy loads, however, leaf springs are still IT. Just look at all the heavy tipper trucks you see on building sites: all on leaf springs, except for Tatra which are on torsion bars. Torsion bars give the comfort of coil springs, combined with the load capabilities of leaf springs and one can only wonder why this suspension system was never adopted by Land-Rover.
I have owned a series III for some 20-odd years now and my wife bought a nice Stage One a couple of months before we got married. This must be a leaf-sprung household. I was even thinking of a leaf spring application for our bed, but that is another matter, not to be discussed here.
One of the most frequently heard objections about leaf springs is that they give a harsh ride. If that is your problem, pack your springs with grease and wrap the whole spring pack in a leather booth, well in the manner of a 1935 Rolls-Royce. Believe me or not, this improves the ride by 50 %. Leaf spring packs are typically rusty and as the leaves rub over each other when absorbing road loads, this rust generates much more friction than grease would do, thus giving a less comfortable ride.
Also, it is the application that dictates the type of spring to be used. Heavy loads demand leaf springs. A good compromise is „parabolic“ leaf springs, which combine comfort and load carrying capability. There is no friction between the leaves of parabolics, hence the comfort and this also allows for more axle travel.
Another issue is reliability. I drove my Stage One to Vladivostok and back in 1992 and it were my leaf springs that brought me home. Imagine being in the middle of nowhere, in Sibir, and breaking a coil spring. End of voyage. In a leaf spring pack, one may break a leaf or two without major consequences and ANY more-or-less equipped workshop can „mend“ this is if the problem becomes a nuisance.
I had left for Russia in April, which brought me into the heart of Sibir when the country started to thaw, creating a bog the size of Europe. The route I followed was not exactly paved roads and when the mud really became a problem, I made it to the nearest railway station, payed a suitable bribe in vodka, Marlboro and some dollars to the Station Chief. Then I waited for the train. When the train left the station, I got behind it and followed it for some 2.800 Km driving on the railway sleepers. Not really fun, but it worked. I eventually arrived in Nakhodka with only 9 broken spring leaves. Not bad, huh. In Vladivostok I waited for 4 new leaf packs to be air shipped to me which only took 72 hrs by DHL. I am absolutely not sure if coil springs would have brought me there with the 950 kg payload I was carrying. (next time I will leave that 480 kg generator/air compressor/welder home, but it seemed a good idea at the time).
Leaf spring maintenance (if any) is easy: the only problem with leaf springs is rust, so packing them with grease is allways a good idea. The other part of this is the bushes. Install polybush whenever and wherever possible, and renew the through bolts once in a while because of the wear or install „greasable“ bolts.